1.Field of the Invention
This invention relates generally to a disk drive device capable of accepting removable cartridge-housed disk media and which records on or reads from said recording medium, and more particularly to improvements in the disk cartridge insertion/extraction mechanism of a slimline disk drive device.
2.Description of the Related Art
A device has been known that records/reads information using a disk cartridge (hereafter referred to as "cartridge") possessing a shutter that selectively covers the magnetic head insertion opening. In such a device, recording/reading is performed by having both the top and bottom heads contact both surfaces of a disk-shaped recording medium (hereafter simply referred to as "disk") stored inside a cartridge. To replace the cartridge, this cartridge is usually moved to a position (insertion/extraction position) where it does not contact the bottom head, in the direction perpendicular to the disk surface, and the other head, i.e., the top head, is moved upward to an insertion/extraction position where it does not contact the cartridge in a similar manner, in order to prevent the cartridge from contacting either the top or bottom head. Naturally, the cartridge insertion/extraction position is located in a spot where the disk does not contact the disk rotation drive mechanism (hereafter simply referred to as "rotation drive mechanism") comprising a drive axis which engages with and drives the hub platform on which the disk is placed, center axis extending from the hub platform, and coupled to the disk.
As overall device size reduction has continued in recent years, the area occupied by the cartridge within an accepting device has been proportionally increasing. Furthermore, as device thickness is reduced, the distance between the recording/reading position and the insertion/extraction position over which the cartridge moves has become a major factor in determining the device thickness. Therefore, schemes have been devised that retreat both the top and bottom heads to avoid the contact between the heads and the cartridge, such that it is possible to insert/extract the cartridge by moving it a smaller distance sufficient for avoiding the center and drive axes.
Conventional cartridge-housed disk drive incorporate a rigid rectangular tube holder barely larger than the disk cartridge it is designed to hold. The cartridge can be reviewed at one end of the tube known as the insertion/extraction slot. The opposing end of this tube holder is also typically left open so that ejection machinery may engage the disk cartridge and to provide easy service access when the cartridge will not eject.
The underside of the tube holder is also left largely open to minimize contact with the chassis and accommodate the central drive mechanism used to rotate the disk within the cartridge yet still provide a slimline profile. In fact, in most conventional holder designs, nearly the entire underside is removed or left open to partially accommodate the chassis. Also, the surface of chassis is shaped to include indentations and grooves to further reduce space margins between it and the holder. However, shaping the chassis in such a manner deteriorates its overall strength and resistance to deformation, especially at the central spindle extending from the central rotary drive mechanism.
Moreover, this structure permits easy deformation of an inserted disk cartridge, particularly the shutter mechanism. Referring to prior art FIG. 6, which illustrates a cross-sectional view of the conventional tube holder 2 and drive chassis 1 with a disk cartridge 9 inserted therein, shutter 91 of the disk cartridge 9 appears shaped like the letter "U" rotated 90.degree. counter clockwise. The top wall 201 and side walls (not shown) of the tube holder 2 restrain travel and deformation of the corresponding walls of the disk cartridge. However, as the underside wall 202 of the tube holder 2 is left largely opened as discussed above, the corresponding disk cartridge surface may deform slightly or warp downward, especially where the cartridge is made of a plastic material as commonly encountered in the art. More importantly, the shutter 91 does not engage the hollow underside wall 202, and it deforms downwardly as well in concert with, or independently of the disk cartridge housing. In other words, the disk cartridge is impeded from movement only with respect to its hard case area excluding the shutter.
Often, as the shutter 91 deforms, the lower projection of tip 91b thereof spans the gap 300b between the disk cartridge and the underside of the tube holder 2 and extends therethrough. This is especially true when the shutter 91 is exposed to manufacturing errors during deformation or the disk cartridge 9 has undergone frequent use. Consequently, this protruding shutter tip tends to contact the center axis or the central rotary drive 50, particularly the hub area 3 and the protrusions 31, 32 extending therefrom, during cartridge ejection operation, thus preventing the ejection. Such a problem can be solved by positioning the cartridge insertion/extraction position sufficiently above and far from the drive mechanism. However, doing so creates a problem of increasing the device thickness to undesirable levels.
Therefore, an object of the present invention is to block undesirable protrusion or extension of the shutter on the rotation drive mechanism side of the holder to prevent contact therebetween. It is a further object of the present invention to implement a shutter blocking or securing device that does not adversely impact in a serious manner the overall thickness of the disk drive device.